package 蓝桥杯;

import java.util.Scanner;

public class xn {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        double x=sc.nextDouble();
        int n=sc.nextInt();
        System.out.println(String.format("%.2f",f(x,n)));
    }
    public static double f(double x,int n){
        if (n==1) {
            return Math.sqrt(n+x);
        }else{
            return Math.sqrt(n+f(x,n-1));
        }
    }
}
